Flue-expander.



F. CLARK. FLUE EXPANDER. APPLIOATION FILED AUG. 19; 1911.

' Patented Dec. 17,1912.

. Ilwe 1" Frederick Clark ms Attomfigsi orun STATES PATENT FFIQ,

FREDERICK CLARK, OF MINNEAPOLIS, MINNESOTA, ASSIGNOB OF ONE-HALF TOWALLACE N. KING, OF WAVERLY, MINNESOTA.

FLUE-EXPANDER.

Specification of Letters Patent.

Patented Dec. 17, 1912.

Application filed August 19, 1911. Serial No. 644,937.

To all whom it may concern:

Be it known that I, FREDERICK CLARK, a

citizen of the United States, residing at the certain new and usefulImprovements in F lue-Expanders; and I do hereby declare the followingto be a full, clear, and exact;

description of the invention, such as will enable others skilled in theart to which it appertains to make and use the same.

This invention has for its object to provide an extremely simple andhighly eflicient flue expander, and to such ends, the invention consistsof the novel devices and combinations of devices hereinafter describedand defined in the claim.

In the accompanying drawings which illustrate the invention, likecharacters inclicate like parts throughout the several views.

Referring to the drawings, Figure 1 is a view chiefly in verticalsection, but with some parts in full, showing the improved flue expanderapplied in working position; and Fig. 2 is a transverse section taken onthe line .21 m of Fig. 1.

An ordinary boiler flue is indicated by the numeral 1, and a flue sheetis indicated by the numeral 2. The expander comprises a sleeve 3, amandrel 4, and expanding rollers 5. The body of the sleeve is of suchsize that it is adapted to be inserted into the flue, and is internallyscrew-threaded. At its extreme outer end, it is provided with a stopflange 6 that is engageable with the outer end of the flue to limit themovement of the said sleeve into the flue. Just inward of the said stopflange 6, the sleeve 3 is enlarged in external diameter and is formedwith radial roller seats 7, in which the rollers 5 are mounted withfreedom for radial movements. These seats 7, at their outer extremities,are of less width than the diameters of the said rollers, so that theyprevent the said rollers from being moved or from falling out of saidseats.

At its intermediate portion, the mandrel 4 is provided with a threadedsection 8 that works in the internal threaded section of the sleeve.Extending outward from the threaded section 8, the mandrel is formedwith an outwardly tapered roller engaging expanding section, or portion9. Also extending outward from the tapered portion 9, the mandrel 4 isreduced a distance suflicient to permit the rollers 5 to rest thereonwhen in idle position. The depth of this reduced portion is suflicientto permit the rollers 5 to clear the fin on the end of the tube 1, atthe time the sleeve 3 is moved to and from working positions. The fin onthe end of the tube 1 is formed at the time the flue is cut to itsproper length. The reduced portion of the mandrel 4, at its extremeouter end, is provided with an angular head 10, to which a wrench, orother tool may be applied for the purpose of rotating the said mandrel.Extending inward from its threaded section 8, the mandrel is providedwith a section of reduced diameter which terminates in an angular head11, to which a wrench or other suitable tool may be applield for thepurpose of rotating said man- All of the above noted parts of themandrel are integrally formed, preferably from hardened tool steel. Therollers 5 are also preferably of hardened tool steel. When the expanderis in working position, the entire body of the sleeve is Within the flueand the rollers are positioned so as to expand the outer end of the flueagainst the seat in the flue sheet. The expanding mandrel may be rotatedby application of a wrench, or other tool, either to the inner or outerend thereof. This is important because sometimes wrenches are located atboth ends of the flue, and it is sometimes desirable to rotate the samefrom one point and sometimes from the other point. When the mandrel isto be rotated by application of a Wrench to its' inner head 11, the saidwrench should be formed on the end of a long rod which is in serted intothe farther end of the flue. The threaded section 8, it will be noted,has the largest diameter of any portion of the mandrel, so that themandrel may be inserted into the sleeve endwise in either direction.

When the tool is positioned, as shown in the drawings, and the mandrelis screwed outward so as to press the rollers against the end of theflue, and the mandrel is then rotated in a direction which screws thesame outward, and further expands the rollers, the action will besubstantially as follows: Under the rolling action which takes placebetween the rollers and the flue, the rollers will travel in the samedirection in which the mandrel is rotated and they will cause the sleeveto rotate in the same direction, but at approximately onehalf as fast asthe said mandrel; and, as is evident, this differential rotary movementbetween the mandrel and spindle will gradually force the mandrellongitudinally outward and force the rollers radially outward. In thisway, the flue will be gradually expanded under rotation of the mandrel,and travel of the rollers on the inner surface thereof. There is,however, a considerable friction between the threads of the spindle andthe sleeve, and in practice, it is found that when the rollers areforced outward too rapidly, this friction between the said threads willbecome so great as to temporarily lock the sleeve and spindle together,and thus, for a time, lock the two in common rotation, therebytemporarily discontinuing the outward feeding movement of the rollersuntil the flue has been expanded suiiiciently to relieve, to someextent, the pressure between the rollers and the flue. In this way, thefeeding action is made perfectly automatic.

The double ended mandrel is especially adapted for use by boiler makers,but for many other classes of work the inwardly projected operating heador shank may be omitted.

WVhat I claim is:

In a flue expander, the combination with an internally threaded sleeveadaptedto be inserted into a flue and having a stop flange at its outerend and roller seats just inward of said stop flange, of rollers in saidroller seats, and a mandrel having an intermediate threaded sectionengaging the internal threads of said sleeve head provided with angularinner and outer heads at its eX- tremities, and formed with a rollerexpanding section that tapers outward from its threaded section, andalso formed with a reduced portion between the outer end of the saidroller expanding section and the said outer head, the said threadedsection of the mandrel being of greater diameter than any of the otherportions thereof, and all parts of the said mandrel being integrallyformed, substantially as described.

In testimony whereof I afliX my signature in presence of two witnesses.

FREDERICK CLARK.

Witnesses:

CHARLES MGMASTERS, H. D. KILGORE.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents.

Washington, I). 0.

